Belfast Lough’s ‘Hero’ Mussels Endangered by Sewage Spills

Blue mussels are considered crucial for Northern Ireland’s water quality, with scientist Matt Service of the Agri-Food and Biosciences Institute (AFBI) describing them as “little ecosystem water treatment plants on their own”. However, in Belfast Lough, where these mussels are cultivated, consistent sewage discharges pose a risk to the environment, the economy, and public health, as detailed in a report from NI Water. According to officials, the lough faces a potential crisis unless investment in its sewage infrastructure is enhanced. The report, titled *The Story of Belfast Lough*, features a senior NI Water official who details the pressures on this “vital natural resource” and the measures necessary for its restoration and protection. Paddy Brow, who serves as the head of the Living With Water Programme (LWWP) at NI Water, authored this report. Mr. Brow stated, “Really, 90% of the excess bacteria we have in Belfast Lough are coming from discharges controlled by Northern Ireland Water.” He added, “It’s also eutrophic, which means it’s likely to have the same algae blooms that happen in Lough Neagh because there’s too much nutrients.” He further noted, “And we know that discharges from Northern Ireland Water are responsible for over 50% of that.” The drainage system in Belfast was initially conceived by Victorian engineers as a combined network, allowing both sewage and storm water to flow through the same pipes. This design choice was influenced by the city’s topography, situated at the base of hills and near sea level. Currently, the Greater Belfast area contains 270 combined storm overflows, a number Mr. Brow indicated should ideally be “about 30 to 50.” Several of these overflows located along the shores of Belfast Lough release discharges over 200 times annually. This implies that any item flushed down a toilet has the potential to enter the lough. Mr. Brow urged, “Please do not flush anything which is not pee, poo and paper.” He further stated, “Our toilets should not be used as a bin.” “We should have the systems that are able to keep things in the sewer when they’re flushed, but we don’t,” he acknowledged. Sanitary products, food wrappers such as crisp bags, condoms, cooking oil and grease, and particularly wet wipes, are identified as the primary contributors to the strain on the sewage system. Mr. Brow noted that the majority of wet wipes contain plastic, which can lead to significant issues. He explained, “When people flush the toilet, the solids settle to the bottom of the pipes.” “The fat combines with wet wipes and they make things called fatbergs,” he continued. This phenomenon, coupled with the “first flush” of water at the onset of rain, requires engineers to be in a constant state of readiness. At Sydenham Wastewater Pumping Station, Northern Ireland’s largest pumping facility, vans are deployed with every rainfall to prevent overflows from becoming obstructed. Mr. Brow stated that the aging infrastructure and insufficient funding for necessary upgrades are impeding Belfast’s growth as “the driving part” of the economy. He elaborated, “It’s got a real need for social housing, and those houses can’t get built at the moment, and that’s a real issue.” Scientists indicate that ongoing spills are exerting pressure on the shellfish industry, an industry that largely ceased operations at the beginning of the 20th Century due to sewage contamination. During the 1990s, mussel beds were established within the inner lough, alongside the designation of a shellfish water protected area. Dr. Matt Service, who leads a team at AFBI responsible for monitoring shellfish and toxic algae, stated, “There are up to three or four thousand tonnes of mussels in the lough. There are about 18 mussels to a kilogram, each filters 1.5 litres of water an hour.” He elaborated, “So you can start to do the sums – effectively, the water in the lough gets turned over by shellfish every 14 days.” These mussels consume nutrients and algae present in effluent from wastewater treatment plants, thereby playing a crucial role in preserving water quality. Dr. Service expressed concern that increased pollution could negatively impact the industry. He explained, “These inner beds are tending to be what’s called a Class C, so that means they can’t really be marketed readily, whereas the outer beds are still a Class B and can go to market, mainly to Holland.” “But if you’ve got increasing areas or increasing episodes of Class C, it would become uneconomic to maintain these beds and because they are artificial beds, they would disappear,” he warned. He concluded, “This feedback loop would begin where mussels are not there to filter the water, and the water quality would begin to decrease.” Recently, Stormont’s Infrastructure Minister, John O’Dowd, asserted that the funding model for NI Water is fit for purpose, a statement challenged by a construction industry organization. On Thursday, a spokesperson for the Department for Infrastructure clarified to BBC News NI that Mr. O’Dowd was “referring to the governance model” and not the current funding level of NI Water. They further stated, “As with all public services there is a need for additional funding, and the minister continues to make the case for this, recently securing an additional £31m for the company.” The spokesperson added, “Other governance models suggested to date involve the introduction of domestic water charges. The minister has repeatedly made his position clear. He will not introduce domestic water charges.” Next week, the program Spotlight will delve into the Belfast Lough sewage pollution scandal, aiming to expose those accountable for jeopardizing both individuals and employment. Spotlight is scheduled for Tuesday, December 3rd, on iPlayer and BBC One NI at 22:40 GMT.